Printing mechanism

ABSTRACT

Printing apparatus preferably for printing numerals in calculating machines is disclosed, such apparatus having a plurality of substantially sector-shaped-type carrying members, each of such members being pivotally mounted and provided with a predetermined number of illustratively impression-type members movable generally radially in the vicinity of the circumference of the sector-shaped portion. A ratchet mechanism is provided on each of the sector-shaped portions for ruling or interrupting movement of each of the type carrying members. A plurality of spring-loaded printing hammers are arranged to strike the type members to print selected characters, each of the hammers being provided with corresponding linkage for controlling its movement. The entire apparatus is preferably mounted on a laterally movable carriage, and electronic coding and sensing may be provided for controlling the apparatus for example, in the event of computerized operation.

United States Patent [72] Inventor Gosta Curt Hjerpe Molndal, Sweden[21] Appl. No. 840,203 [22] Filed July 9, 1969 [45] Patented Jan. 11,1972 [73] Assignee Ing. F-a Preko Molndal, Sweden [32] Priority Nov. 14,1968 [33] Sweden [31] 15447/68 [54] PRINTING MECHANISM 23 Claims, 8Drawing Figs.

[52] U.S.Cl. 10l/93C [51] Int. Cl B4lj [50] Field ofSearch 101/93 MN,

[56] References Cited UNITED STATES PATENTS 1,608,837 11/1926 Bryce101/93 C 1,705,983 3/1929 Lasker et a1. lOl/93 C Primary ExaminerRussellR. Kinsey AttorneyDarby & Darby lOl/93C 101/93C ABSTRACT: Printingapparatus preferably for printing numerals in calculating machines isdisclosed, such apparatus having a plurality of substantiallysector-shaped-type carrying members, each of such members beingpivotally mounted and provided with a predetermined number ofillustratively impression-type members movable generally radially in thevicinity of the circumference of the sector-shaped portion. A ratchetmechanism is provided on each of the sector-shaped portions for rulingor interrupting movement of each of the type carrying members. Aplurality of spring-loaded printing hammers are arranged to strike thetype members to print selected characters, each of the hammers beingprovided with corresponding linkage for controlling its movement. Theentire apparatus is preferably mounted on a laterally movable carriage,and electronic coding and sensing may be provided for controlling theapparatus for example, in the event of computerized operation.

PATENTED JAN! 1 1972 SHEET 2 [1F 8 1. ow 9n minnow 1 m2 3.333.499

SHEET 3 [IF 8 PATENTED JAN] 1 I972 SHEET 4 BF 8 PATENTEU JAM 1 i972SHEET 5 BF 8 PATENTED JAN] 1 m2 SHEET 6 OF 8 PATENTED JAN] 1 1972 SHEET7 [IF 8 mm mm mm PATENTED mu 1 1972 31 33499 saw a or a 39 fTTfiTiW 813H|IIIHHH 1 HHHHI'I' 1 PRINTING MECHANISM The present invention relatesto a printing mechanism particularly for printing numerals in, forexample, calculating machines and of the type comprising substantiallycircle-sector-shaped-type carriers adapted to be set and provided withradially movable types, means for ruling the type carriers in setpositions, preferably spring-loaded printing hammers and cocking means,and a device for releasably hooking said printing hammers.

The invention has as its object to produce a printing mechanism whichsimultaneously satisfies a plurality of very far-reaching desires, suchas a very small spacing, for example 0.1 inches for adjustment totypewriter text, very small assembly height, for example for renderingpossible a laterally movable attachment in combination with a typewriterof the writing-ball type, and complete flexibility in the choice ofmechanic or electric control of the printing mechanism with allowing fora high printing capacity. Further desires to be satisfied by theinvention are low manufacturing costs, safe operation and long life.

A printing mechanism for the aforesaid objects is characterizedaccording to the invention substantially in that every decade of theprinting mechanism comprises two detail groups located to the side ofeach other and lying substantially entirely within the type width, oneof said groups comprising the substantial part of the type carrier whichshows a substantially radial portion and connected therewith acircumferential portion, said group also comprising a ruling hookdisposed in the space inside of the circumferential portion for engagingwith cogs formed on the inside thereof, for which ruling hook isprovided a blocking member, the other of said detail groups comprising amember disposed on the circumferential portion of the type carrier forsupporting radially inwardly directed shanks of the types and apreferably spring-loaded printing hammer disposed in the space inside ofsaid supporting member.

A suitable embodiment of the invention will be described in greaterdetail in the following, with reference to the accompanying drawings inwhich:

FIG. I is a sectional view of the printing mechanism showing the typecarrier in initial position with the printing hammer cocked;

FIG. 2 is a sectional view of the printing mechanism showing the typecarrier latched in a setting position;

FIG. 3 is a view similar to FIG. 1 showing the hammer in a printingposition;

FIG. 4 is a view similar to FIG. 2 showing the type carrier in an upperend position;

FIG. 5 is an elevational end view of the printing mechanism showing thedrive shaft of the mechanism and motion-transmitting members forpositioning a portion of the printing mechanism;-

FIG. 6 is a view similar to FIG. 5 showing linkage for suspending andpositioning the printing mechanism.

FIG. 7 is a perspective assembly drawing of the printing mechanism andpartially shown in an exploded view, FIG. 8 is a block diagram referringto an electronic unit for controlling the printing mechanism.

As appears most clearly from FIGS. 1-4, each of the types 1 of theprinting mechanism is supported by substantially sectorshaped typecarn'ers 2, in such a manner, that each of such type carriers isprovided with types corresponding to the numerals 0 through 9. Each ofthe types 1, as appears most clearly from FIG. 3, is arranged so as tobe radially movable in relation to the type carrier. Each of the typecarriers 2, which freely can pivot about a shaft 3 common to all typecarriers, comprises an entirely plane portion which preferably may bepunched out of sheet metal. Said plane portion shows a substantiallycircular hub, a substantially radially directed portion and asubstantially circumferential portion projecting from the end of saidradially directed portion, each of the types being mounted on one sideof said circumferential portion. For this purpose, each of the types isso designed that its shank projects substantially radially in relationto the type carrier and is movably placed in a bearing portion 2a whichis rigidly connected with the circumferential portion of the typecarrier, said bearing portion 20 on the side facing towards the typeshank being provided with radiated grooves for the type shanks. Thebearing portion 2a preferably may be formed of synthetic resin and begiven a thickness such that the bearing portion together with theremaining part of the type carrier is lying entirely within the typewidth, although the type width may be chosen very small, for example 0.1inches, in order to be in agreement with the type width usual attypewriters.

In the vicinity of the hub portion of every type carrier 2 a dog member2b is pivotally rivetted, which is provided with. a substantiallyhook-shaped portion and loaded by a tension spring 20 mounted betweensaid dog member and the radial portion of the type carrier, so that saiddog member with its hook-shaped portion releasably embraces a rod 4aassociated with a double setting bridge 4, said rod being adapted tocooperate with the dog members of all type carriers, in such a manner,that the setting bridge is rigidly connected with the shaft 3 common toall type carriers. Said shaft 3, as will be described later on, isadapted during every setting and printing operation to oscillate inclockwise direction between the starting position illustrated in FIG. 1and a position somewhat past that shown in FIG. 3.

Upon the clockwise rotation of shaft 3 from the position shown in FIG.I, the rod 4a by means of the dog members 2b causes the type carriers 2to participate in the swing of the setting bridge about the shaft 3 tothe upper end position of the swing shown in FIG. 4. Said upper positionis determined by a check rod 5 which extends through the printingmechanism and against which the upper end edge of a recess 2e made inthe hub portion of every type carrier is intended to abut, provided thatthe type carriers are not therebefore obstructed in their swing in aswing position corresponding to a type being in position for printing.When a type carrier during its clockwise swing thus is blocked forsetting, as it is illustrated in FIG. 2, the hook-shaped dog member 2bof the type carrier, as shown in FIG. 3, is swung out of the engagementwith rod 4a against the action of spring 20 and by the action of saidrod, which rod thereafter is allowed to slide along a surface of the dogmember 2b, which surface is peripheral in relation to the shaft 3.During the anticlockwise return motion of the setting bridge 4, when therod 4a again arrives at the position shown in FIG. 2, the dog member 2bby action of spring 2c again is swung into engagement with said rodwhich simultaneously is caused to abut to a stop surface 2d of the typecarrier for nonresiliently resetting the type carriers to the startingposition shown in FIG. I.

For rendering it possible to block the type carriers in individualsetting positions during the clockwise setting motion, every typecarrier is provided on the inside of its circumferential portion with acog or ratchet-arrangement 2f corresponding to the existing types, withwhich cogs a corresponding latch or pawl 7 pivotally mounted on a shaft6 is intended to be engaged by action of a locking member which isdesigned as an arm 9 pivotally mounted about a shaft 8. Said arm isloaded by a spring 10in that direction of swing in which the latch 7 isactuated in the direction of engagement, as appears from FIG. 2. Saidarm 9 is adapted to be swung in anticlockwise direction to the endposition of its swing and thereby to tension the spring 10, both duringthe setting motion of the type carrier in question to the blockingmoment and during the resetting motion, as shown in FIG. 4, in whichposition the arm is adapted releasably to be retained in a way whichwill be described later on. In this cocked position of the arm 9 thecorresponding latch 7 is swung in clockwise direction to thenonoperative end position of its swing by cooperation between the lowerside edge of the'arm 9 and the corresponding upper edge surface of afinger 7a projecting substantially radially from the lower end portionof the latch in relation to the shaft 6. The latch, however, in itsoperative end position for blocking the type carrier 2, as shown in FIG.2, is

actuated substantially by an end edge of arm 9 formed downwardly withincreasing radial distance from shaft 8. Said end surface of the arm 9thereby cooperates by key effect with an arc-shaped edge surface of thelatch 7, the key angle as well as the positions of said contact surfacesin relation to the shafts 6 and 8 so being chosen that the latch 7cannot be moved out of its position as long as the arm 9 by action ofthe spring 10 is retained in its position shown in FIG. 2.

The swinging motion of arm 9 to the swing end position shown in FIG. 4,by which motion the spring 10 is tensioned and the latch 7 is swung toits nonoperative position, is effected by a resetting bridge 11 commonto all arms 9, which bridge by two end walls 110 is pivotally mountedabout the shaft 6 for the latches 7. The end walls 11a of said resettingbridge are connected with one another at their end portions remote fromthe shaft 6, by means of a rod llb abutting to the upper surfaces of thearms 9, said rod upon clockwise swing of the resetting bridge effectingthe anticlockwise swing of the arms 9 to said position shown in FIG. 4.The clockwise swing of the resetting bridge 11 is intended to beeffected by two cam disks [2 abutting to radial sides on the end wallsIla in question, said cam disks being rigidly connected with a shaft 13.Said shaft 13, as the aforementioned shafts 3, 6 and 8, is mounted inend walls 14 intended for the printing mechanism. Said end walls 14 alsosupport the check rod 5, a holder 15 intended in part for the springs10, and guide members l6, l7 and 18, respectively, provided for the typecarriers 2, the latches 7 and the arms 9, respectively.

As it should have appeared from the above functional relation betweentype carrier 2, latch 7 and arm 9, the two lastmentioned details may beformed entirely plane, like the type carrier 2, by punching them out ofsheet metal, and they may be arranged in a plane in common with the typecarrier, all three of said details thus requiring very little of thewidth of the printing mechanism, preferably only one-third of theselected type width. According to the invention, the remaining part ofthe type width which is utilized in part for the bearing portion 2aintended for the types 1 and to some extent also by the dog member 2b,therefore can be utilized for the printing function.

In the space between the bearing portion 2a and the shaft 3 forsupporting the type carriers, a printing hammer 19 is provided to theside of latch 7 and arm 9, said hammer being pivotally mounted about theshaft 6 intended in part for the latches 7, in such a manner, thatprinting hammer and latches are arranged alternatingly on said shaft.The complete set of printing hammers and latches is enclosed near to theend walls 14 by the end walls lla of the resetting bridge 11 which alsoare pivotal about the shaft 6. Each of the printing hammers 19, which isprovided with a head 19a for striking against the angular end portion ofthe type shank of a type I, is spring loaded in the striking directionby a tension spring 20 stretched between the lower end portion of theprinting hammer and the holder 15 for the springs 10. At some distancefrom shaft 6 the printing hammer is formed with a projection 19!)directed substantially to the shaft 3, which projection for cocking thehammers 19 in clockwise direction is adapted to cooperate with a secondrod 415 at the double setting bridge 4 intended for setting the carriers2. Said second rod 4b, upon the resetting motion of the setting bridge 4from the position shown in FIG. 3 to the starting position shown in FIG.1, causes by:- directly acting on said hammer projection 19b the hammerto swing into the cocked position shown in FIG. 1, in which position aratchet 19c is caused to engage with a hooking bar 210 of the hookingbail 21, which hooking bar is intended for all hammers and extendsbetween the two end wall portions 21b of the hooking bail which aredisposed near to the end wall plates 14 of the printing mechanism. Thehooking bail 21 is mounted with its two end wall pieces pivotally aboutbearing bushings 22 acting as a bearing for a shaft 23 which will bedescribed later on. Each of the two end wall pieces 21b of the hookingbail 21 is formed with an upwardly directed projection, the upper end ofwhich abuts to a corresponding cam disk 24. The two cam disks 24 arerigidly connected with the aforementioned shaft I3 which, as appearsfrom FIGS. 5 and 7, is coupled with the shaft 23 by means of atransmission gear 25 with the gear ratio 1:1. It further appears fromFIGS. 5 and 7 that on shaft 13 is arranged an eccentric disk 26 on whichone end of a rod 27 is mounted, the other end of said rod beingarticulated by a journal 28 with an arm 29 which projects radially fromand is rigidly connected with the shaft 3. Upon rotation of the shaft13, thus, both the cam disks l2 and 24 and the eccentric disk 26 arecaused to rotate and thereby by means of the rod 27 to impart to the arm29 and, thus, to the shaft 3 an oscillating motion, in which motion thesetting bridge 4 is caused to participate.

On the shaft 13, furthermore, is rigidly mounted an additional eccentricdisk 30, on which is rotatably mounted one end of a link rod 31, theother end of which by means of a threaded stud 33 is articulated with asuspension means 32 for the mounting of the printing mechanism. In thelower corner portions of those end edges of the end wall plates 14 ofthe printing mechanism which face towards a paper platen 34, as appearsmost clearly from FIGS. 2 and 4, recesses [40 are arranged which areintended to receive each its of the aforementioned bushings 22, each ofwhich is rigidly connected with a corresponding portion of thesuspension means 32. For retaining the printing mechanism in theposition shown in FIG. 6 relative to the bushings 22, a correspondingmounting member 35 rotatably mounted about the bushing 22 in question isreleasably screwed into the outside of every end wall 14. Thus, upon therotation of shaft 13 the printing mechanism, as indicated by the arrowa, is swung upwards and downwards by action of the eccentric disk 30 andby means of the link rod 31, in such a manner, that the printingmechanism is swung about the bushings 22, i.e., concentrically with theshaft 23 rotatabiy mounted in said bushings, so that during saidswinging motion of the printing mechanism the center distances betweenthe shafts 23 and l3 remain unchanged. The eccentric disk 30 and thelink rod 31 as well as the cam disks l2 and 24 together with thecorresponding projections 21c of the hooking bail are maintained intheir definite lateral positions by action of a guide cam 36 mounted onthe inside of every end wall plate 14, as shown in FIGS. 4 and 7.

In the embodiment illustrated in FIG. 7 the printing mechanism ismounted laterally movable, in such a manner, that the suspension means32 comprises a carriage which in the embodiment shown is a substantiallyU-shaped bar 32a. Said bar, on the inside of its upwardly facing legportions, is provided with V-shaped grooves for receiving a number ofballs 32b intended to cooperate with corresponding grooveshaped recessesin a horizontal guide member 37. Said guide member 37 is intended to berigidly connected with end wall plates 38 comprised in the machine inquestion, for example an accounting machine, of which plates only one ispartially illustrated in FIG. 7. Said end wall plates 38 also areintended to support the roll 34 of the machine and to serve as a bearingfor the shaft 23 intended for driving the printing mechanism, whichshaft 23 besides is axially fixed in the end wall plates 38. The onecogwheel in the transmission gear 25 which is Iocated on the shaft 23,thus, can be moved along the shaft 23 together with the printingmechanism, whereby the printing mechanism by the rigid connectionbetween the shaft 23 and said cogwheel is driven from the shaft 23independent of the moving position of the printing mechanism.

The arms 9, as mentioned before, are intended to be retained in theircocked positions shown in FIG. 4 against the action of the springs 10,in which positions the corresponding latches 7 are moved into theirnonoperative positions. Said retaining capacity is intended to beeffected by an electromagnet 39 corresponding to every arm 9, each ofsaid arms being provided with an armature 9a which corresponds to themagnet in question and in cocked position of the arm abuts to the statorof the electromagnet. Said arms 9 are made of nonmagnetic material, inorder to prevent unfavorable magnetic in fluence via the arms 9 to thelatches 7 and other adjacent details. The electromagnets 39, which forspace reasons are placed in staggered relationship in the longitudinaldirection of the arms 9 and arranged in groups of three magnets which intheir turn are placed to the side of each other, are mounted on andelectrically connected to a printed circuit card 40, which is mounted onthe upper portion of the guide cam 16 and in the end wall plates 14 ofthe printing mechanism. As long as current flows through theelectromagnets, the arms 9 are maintained in their cocked positions, butas soon as the current flow is interrupted by anyone of theelectromagnets, the corresponding spring by means of the associated arm9 moves the corresponding latch 7 into engagement with the cogs 2f ofthe type carrier 2 in question. If said release of the magnets 39 takesplace during the setting motion imparted to the type carriers 2 by thesetting bridge 4, the type carriers will be stopped by the latches 7 inquestion in positions corresponding to the release moment of theelectromagnets in question during the setting motion. This embodiment iswell adapted to be fitted to electronic as well as electromechanicalcalculating machines or the like, but the printing mechanism also can beimagined to be fitted to purely mechanical machines, in which case theelectromagnets 39 can be exchanged against mechanic members.

In the embodiment shown the printing mechanism is intended for use inconnection with electronic calculating machines or the like at which thenumeral values are stored as binary information in an associated storageunit. FIG. 8 illustrates in a schematic way by means of a block diagrama suitable embodiment of an electronic control unit intended forreleasing the electromagnets 39, the operation cycle of said unit beingintended to be synchronized with the setting course of the printingmechanism by action of a photoelectric position transmitter comprised inthe printing mechanism, which transmitter is illustrated in FIGS. 5 and7 and indicated also in FIG. 8. In the embodiment shown the positiontransmitter comprises a radially projecting arm 41 which is rigidlyconnected with the shaft 3 and at its end portion remote from said shaftformed with an arc-shaped portion 41a projecting axially and beingconcentric with the shaft, which portion 41a is provided with fiveaxially distributed and circumferentially extending rows with lightopenings designated by A, B, C, D and E. On one side of said axialportion 41a a tube lamp 42 is arranged which is intended to illuminateall hole rows and, as indicated in FIG. 5, disposed in a suitable lamphousing 43. On the other side of said portion 41a a group of photodiodesor the like corresponding to the hole row and designated by 44 arearranged on a holder 45 mounted between the end walls 14 of the printingmechanism, which holder as indicated by dash-dotted lines in FIG. 5preferably is part of a housing assembled to one unit with the lamphousing 43.

The numerals to be set for printing by locking the type carrier 2 inquestion during the clockwise swing motion of the setting bridge 4 arein the embodiment in question intended to be registered in the storageshown in FIG. 8. Said storage preferably is a core storage in which saidnumeral registrations are intended to be sensed by decades and onenumeral after the other in accordance with the order of the numerals inthe setting direction on the type carriers. For rendering possible saidsensing of the numerals one by one, the electronic part must be givencontinuous information on the current setting position of the typecarriers, i.e., the electronic part must be kept informed on whichnumeral common to all type carriers is in setting position in the momentin question. This information is given to the electronic part by actionof the code formed by the hole rows B-E, said code being sensed by thecorresponding photodiodes 44 which transform the light signals arrivingthrough said holes into corresponding electric signals which through aline group 46 are fed to a control transformer which, as appears fromFIG. 8, also is connected to corresponding outlets 47 of the corestorage. Said outlets 47 from the core storage are further connected, asalso is shown, to a sensing member for unessential noughts, i.e., suchnoughts which precede the number proper and, therefore, are

not to be printed. Said sensing member is connected by a line 48 to agate 49 to which also the outlet line 50 of the control transformer isconnected. The outlet of the gate 49, as indicated schematically, canselectively be connected in proper order to a number of magnetoswitchcircuits corresponding in number to the release magnets 39, the numberof said switch circuits, thus', being 13 decades. The connection of theoutlet of gate 49 to the different switch circuits is effected by theaction of a decade selector shown in the drawing, which selector also isintended synchronously to shift an ingoing sensing line 51 betweeninlets of the core storage corresponding to the 13 decades. The shiftingof the connections in proper order between the magnetoswitch circuitsand the different inlets of the storage is effected by toggle circuits(not shown), in such a manner, that the decade selector for thesynchronous stepping is controlled by a pulse generator which may bedesigned so as to emit a continuous sequence of pulses while the decadeselector performs only one shifting sweep for every time a startingsignal caused by a corresponding light opening in the hole row A isreceived from the corresponding photodiode 44 via a connecting line 52.Such a starting signal can also be supplied to the decade selector viaan inlet 53.

In the embodiment in question the type carriers 2 have no types in thestarting position shown in FIG. 1. After this position the types arearranged in the order of 0,l,2,39 and may thereafter, for example, befollowed by a comma symbol. Immediately prior to the start of theclockwise swing motion of setting bridge 4 for setting the type carriers2, a start signal is supplied to the decade selector via the inlet 53whereby the decade selector timed with the signals received from thepulse generator senses the storage portions corresponding to the decadewhile simultaneously switching the outlet of gate 49 between thecorresponding magnetoswitch circuits. During this sensing sweep whichstarts with the 13 decade and continues in proper order to the firstdecade, usually first a number of unessential noughts are met. Saidnoughts are transmitted via the outlet lines 47 of the storage to thecontrol transformer as well as to the sensing member for the unessentialnoughts, which latter member via the outlet line 48 normally sends asignal causing the gate 49 to assume a state of conductive function. Asthe photodiodes 44 corresponding to the hole rows B to E in acorresponding starting position of the position transmitter 41 emitsignals corresponding to zero to the control transformer, everyregistration of an unessential nought received from the storage effectsan outgoing signal via the outlet line 50 of the control transmitter,the gate 49 and further to the magnetoswitch circuits in question whichthereby interrupt the current flow through the corresponding magnets 39.Hereby the corresponding type carriers 2 are locked in their startpositions by action of the associated latches 7 which are moved intotheir locking positions by ac tion of the springs 10 and by means of thearms 9. Said locking takes place by decades in a rapid rhythm andsynchronously with the stepping of the decade selector to correspondingdecades in the store of the magnetoswitch circuits, which stepping iscontrolled by the pulse generator. When during this first sensing sweepa registration of a numeral differing from zero is met in the storage,also this numeral is transmitted via the outlet lines 47 of the storageboth to the control transmitter and to the sensing member forunessential noughts, said sensing member being so designed that thesignal going out via the line 48 changes polarity and thereby interruptsthe current flow through the gate 49.

Signals possibly going out from the control transmitter via the outletline 50, therefore, will not be transmitted to correspondingmagnetoswitch circuits even if such signals are emitted by the controltransmitter due to essential noughts met during the continued part ofthe first sensing sweep. The latches 7 corresponding to essentialnumerals in decades in question, therefore, are retained in theirnonoperative function positions shown in FIG. 4 and, therefore, the typecarriers 2 corresponding thereto are allowed to follow with the settingbridge 4 when it starts its clockwise setting-motion. At the beginningof the setting motion of the type carriers 2 the outgoing signal of thesensing member for unessential noughts again is caused to changepolarity and thereby also the position transmitter 41 assume the firstsetting position in which the type carriers are provided with noughts,the signals emitted from the photodiodes 44 corresponding to the holerows B to E are not changed, so that the control transmitter still emitsan outgoing signal for every zero registration read from the storage.As, however, the registrations corresponding to the unessential noughtsalready previously have caused the release of the latches 7 associatedwith the corresponding magnets 39, these registrations now are not ofany importance, nor will such registrations sensed from the storagewhich refer to numerals differing from zero cause any release of magnets39 associated with corresponding decades, because these sensedregistrations will be compared with the signals which represent zero andare supplied to the control transmitter from the photodiodes 44 via thelines 46. During this second sensing sweep which is started by a signalemitted by the corresponding photodiode 44 through one of the firstlight openings in the hole row A to the decade selector via the line 52,thus, the current flow will be interrupted only for the electromagnets39 corresponding to decades in which essential noughts have been sensed.The type carriers comprised in these decades, thus, will be locked inthe setting position of the nought by associated latches 7.

When the type carriers 2 and thereby also the position transmitter 41assume the next setting position corresponding to the numeral 1, a lightopening in the hole row B will produce an outgoing signal from thecorresponding photodiode 44 whereby the control transmitter so isswitched that only registrations met in the storage and corresponding tothe numeral I produce an outgoing signal via the line 50 and gate 49,which is maintained in conductive function state during the entirecontinued setting operation. Possible registrations in the storage whichcorrespond to numeral 1, thus, will in the corresponding decades inquestion cause the locking of the type carriers in the setting positionof numeral one. In a corresponding way all numerals registrated in thestorage will during the sensing sweep in question he set in the decadesintended. The time required in every setting position for setting alldecades does not exceed -l0 ms. as long as the number of decades can beheld within reasonable limits and, therefore, the complete setting ofthe printing mechanism can be effected very rapidly, which is highlyimportant as hereby the applicability of the printing mechanism can beincreased to a high degree.

The setting of the printing mechanism is made by starting from thebackswept position shown in FIG. 6, in which position the shaft 13 ofthe printing mechanism is held in the position shown in said Figure aswell as in FIGS. 1, 5 and 7 the drive shaft 23 being in itscorresponding position shown in the same Figures. in this startingposition of the printing mechanism the sensing of possible unessentialnoughts is commenced, which thereby are set by locking correspondingtype carriers 2 in their starting positions shown. In direct connectiontherewith the drive shaft 23 of the printing mechanism is started forone clockwise revolution, during which the shaft 13 driven thereby isrotated through one anticlockwise revolution by means of the geartransmission 25. As soon as the anticlockwise rotation of the shaft 13has commenced, the type carriers 2 are swung for their setting inclockwise direction by action of the setting bridge 4, the rotation ofsaid bridge being effected by action of the eccentric disk 26 by meansof the rod 27, the journal 28, the arm 29 and the shaft 3, which alsoeffects the swing motion of the position transmitter 41 synchronizedwith the setting bridge. in the anticlockwise rotation of shaft 13 alsoparticipate the cam disks 12 and 24 and the eccentric disk 30, of whichsaid latter by means of the link arm 31 causes the printing mechanism toswing to the printing position indicated by dash-dotted lines in FIG. 6.After the completion of the setting motion and when the printingmechanism has arrived in its upper end position of the swing, thehooking bail 21 with its hooking bar 21a is swung out of the engagementwith the spring-loaded printing hammers 19 by action of the cam disks 24acting upon the hooking bail. Hereby the printing hammers are caused tostrike against the types corresponding to the setting position of thetype carriers 2 in question and thereby the types are caused to strikeagainst the writing sheet 340 indicated by a dash-dotted line. An inkedribbon (not shown) is to be placed in usual manner between the types andthe written sheet.

Subsequent to the printing the printing mechanism again is swung to thelower end position of its swing as shown in H6. 6 and simultaneously thesetting bridge 4 with the rod 4b returns the printing hammers 19 totheir cocked positions in which they are hooked up by the spring-loadedhooking bail 21. Said bail abuts to a lower portion of the cam disk 24after the printing hammers have arrived at their cocked positions. Aftercompleted printing also the arms 9 are returned to their cockedpositions shown in FIG. 4 by action of the resetting bail 11 controlledby action of the cam disks 12, the latches 7 thereby being moved out ofengagement with the cogs 2f of the type carriers. in connectiontherewith and simultaneously with the cocking of the printing hammers 19also the type carriers 2 are returned to their starting positions byaction of rod 4a of the setting bail 4, which rod thereby cooperateswith the stop surface on each of the type carriers. While the printinghammers 19 are cocked and the type carriers 2 are reset also theposition transmitter 41 is returned to the upper end position of itsswing shown in FIGS. 5 and 7. When the printing mechanism in this wayhas reassumed its starting position, the drive shaft 23 and thereby theshaft 13 which have carried out each its revolution are stopped, thestarting and stopping of the drive shaft 23 preferably being effected bymeans of a coupling (not shown) by which the drive shaft 23 can becoupled to an electromotor (not shown) or the like. For service andoverhaul of a printing mechanism of the aforedescribed type, themechanism very easily can be removed from the machine in question byloosening the studs 33 screwn in whereby the link arms 31 are released,and by loosening the holding members 35 from the end wall plates 14 ofthe printing mechanism. If the printing mechanism entirely is to beremoved from the machine, also a cable (not shown) intended for theelectromagnets 39, the tube lamp 42 and the photodiodes or the like 44,must be disconnected, which very simply can be done while it isconnected to the machine, by a multipole plug or the like.

The invention, of course, is not restricted to the embodiments describedabove and illustrated in the drawing, but can to its details be variedwithin the scope of the inventive idea.

What 1 claim is:

1. Printing apparatus for applying printed characters to paper or thelike, said apparatus comprising:

a movable housing;

a plurality of type carrying members pivotally connected to saidhousing, each of said members'having a substantially sector-shapedportion and an arm portion extending substantially radially from saidsector portion;

ratchet means forming part of each of said sector portions forinterrupting movement of respective ones of said members;

a plurality of type members mounted on each of said sector portions andmovable generally radially in the region of the circumference of saidportion;

a plurality of printing hammers pivotally connected to said housing,each of said hammers being associated with one of said type carryingmembers; and

means for controlling the movement of said hammers to cause said hammersto engage selected ones of said type members, thereby to move said onesof said types into printing position.

2. Apparatus as in claim 1 wherein said ratchet means comprises aplurality of inclined teeth on the inner perimeter of said sectorportion.

3. Apparatus as in claim 2 further comprising, a plurality of pawlmembers connected to said housing, each of said pawl members beingmovable to engage said inclined teeth of corresponding ones of saidsector portions and a plurality of locking members, each of said lockingmembers being engageable with one of said pawls to predispose said pawlfor engagement with selected ones of said teeth.

4. Apparatus as in claim 3 further comprising, a plurality of dogmembers, each of said dog members being pivotally connected to one ofsaid type-carrying members and biased in one direction, and firstbridging means for simultaneously positioning each of said type-carryingmembers, said dog members being adapted releasably to engage saidbridging means.

5. Apparatus as in claim 4 wherein said controlling means comprisesspring means for biasing each of said hammers in the striking positionrelative to said type members, and latching means forming part of saidfirst bridging means for releasably engaging each of said hammers tomove said hammers against the bias of said spring means.

6. Apparatus as in claim 5 wherein, with respect to each of said typecarrying members, said arm portion, said inclined teeth, said pawl andsaid locking members are substantially coplanar.

7. Apparatus as in claim 6 wherein, with respect to each of said typecarrying members, said dog member and said printing hammer aresubstantially coplanar.

8. Apparatus as in claim 7 wherein each of said locking members ispivotally mounted relative to its corresponding pawl member, andcomprises first and second surfaces for engaging said pawl, said firstsurface being eccentric relative to the pivot point of said lockingmember whereby one end of said surface is radially farther from saidpivot point than other parts of said first surface.

9. Apparatus as in claim 8 further comprising second bridging meanssimultaneously engageable with each of said locking members for settingsaid locking members to a first position whereby said second surfaceengages said pawl to move said pawl out of engagement with said ratchetteeth, each of said locking members being spring biased to a secondposition in which said second surface is at least partially disengagedfrom said pawl whereby said pawl engages said ratchet teeth.

10. Apparatus as in claim 9 further comprising electromag netic meansfor actuating each of said locking members.

11. Apparatus as in claim 10 wherein said pawl members and said secondbridging means are pivotally mounted about a common axis.

12. Apparatus as in claim 11 wherein said printing hammers are pivotallymounted about said common axis.

13. Apparatus as in claim 12 wherein said latching means comprises alatching member pivotally mounted relative to said hammers andsimultaneously engageable with a portion of each of said hammers, saidlatching member being movable into and out of the path of motion of saidhammers.

14. Apparatus as in claim 13 further comprising means for moving saidhousing into at least three positions relative to the paper, one of saidpositions being a printing position.

15. Apparatus as in claim 14 wherein said moving means comprises a firstrotatable shaft connected to said housing.

16. Apparatus as in claim 15 wherein said moving means furthercomprises, a second rotatable shaft connected to said housing, and meansconnecting said first and second shafts for transmitting movement of oneof said shafts to the other of said shafts, said second shaft having afirst eccentric member mounted thereon and connected to said housing toinduce oscillatory movement of said housing between said threepositions.

17. Apparatus as in claim 16 further comprising a second eccentricmember mounted on said second shaft and connected to said first bridgingmeans to induce oscillatory movement in said bridging meanssimultaneously with said oscillator movement of said housin 8. Apparatusas in claim 7 further comprising a plurality of restraining bails, eachof said bails being engageable with one of said hammers, and a pluralityof cam members connected to said second shaft, each of said cam membersbeing engageable with corresponding ones of said restraining bails formoving said bails selectively into and out of engagement with saidhammers.

19. Apparatus as in claim 18 further comprising a cam memberperiodically engageable with said second bridging means to actuate saidlocking members.

20. Apparatus as in claim 19 wherein each of said restraining bails ispivotally mounted on said first shaft.

21. Apparatus as in claim 20 wherein said housing is adapted for lateralmovement along said first shaft.

22. Apparatus as in claim 21 further comprising carriage means havingfirst bearings connected to said first shaft and second bearingsconcentric with said first bearings for the pivotal bearing of saidhousing.

23, Apparatus as in claim 22 further comprising an elec tronic storageregister to emit electric impulses for actuating said electromagneticmeans, a code member movable synchronously with said first bridgingmeans and having a plurality of machine readable code configurations,each of said configurations corresponding to one type position of saidtype carrying members, and means for scanning said code configurations,said scanning means being adapted according to a scanned code to emit anelectric signal for sensing said storage register with respect to thepresence of a corresponding character registration.

1. Printing apparatus for applying printed characters to paper or thelike, said apparatus comprising: a movable housing; a plurality of typecarrying members pivotally connected to said housing, each of saidmembers having a substantially sectorshaped portion and an arm portionextending substantially radially from said sector portion; ratchet meansforming part of each of said sector portions for interrupting movementof respective ones of said members; a plurality of type members mountedon each of said sector portions and movable generally radially in theregion of the circumference of said portion; a plurality of printinghammers pivotally connected to said housing, each of said hammers beingassociated with one of said type carrying members; and means forcontrolling the movement of said hammers to cause said hammers to engageselected ones of said type members, thereby to move said ones of saidtypes into printing position.
 2. Apparatus as in claim 1 wherein saidratchet means comprises a plurality oF inclined teeth on the innerperimeter of said sector portion.
 3. Apparatus as in claim 2 furthercomprising, a plurality of pawl members connected to said housing, eachof said pawl members being movable to engage said inclined teeth ofcorresponding ones of said sector portions and a plurality of lockingmembers, each of said locking members being engageable with one of saidpawls to predispose said pawl for engagement with selected ones of saidteeth.
 4. Apparatus as in claim 3 further comprising, a plurality of dogmembers, each of said dog members being pivotally connected to one ofsaid type-carrying members and biased in one direction, and firstbridging means for simultaneously positioning each of said type-carryingmembers, said dog members being adapted releasably to engage saidbridging means.
 5. Apparatus as in claim 4 wherein said controllingmeans comprises spring means for biasing each of said hammers in thestriking position relative to said type members, and latching meansforming part of said first bridging means for releasably engaging eachof said hammers to move said hammers against the bias of said springmeans.
 6. Apparatus as in claim 5 wherein, with respect to each of saidtype carrying members, said arm portion, said inclined teeth, said pawland said locking members are substantially coplanar.
 7. Apparatus as inclaim 6 wherein, with respect to each of said type carrying members,said dog member and said printing hammer are substantially coplanar. 8.Apparatus as in claim 7 wherein each of said locking members ispivotally mounted relative to its corresponding pawl member, andcomprises first and second surfaces for engaging said pawl, said firstsurface being eccentric relative to the pivot point of said lockingmember whereby one end of said surface is radially farther from saidpivot point than other parts of said first surface.
 9. Apparatus as inclaim 8 further comprising second bridging means simultaneouslyengageable with each of said locking members for setting said lockingmembers to a first position whereby said second surface engages saidpawl to move said pawl out of engagement with said ratchet teeth, eachof said locking members being spring biased to a second position inwhich said second surface is at least partially disengaged from saidpawl whereby said pawl engages said ratchet teeth.
 10. Apparatus as inclaim 9 further comprising electromagnetic means for actuating each ofsaid locking members.
 11. Apparatus as in claim 10 wherein said pawlmembers and said second bridging means are pivotally mounted about acommon axis.
 12. Apparatus as in claim 11 wherein said printing hammersare pivotally mounted about said common axis.
 13. Apparatus as in claim12 wherein said latching means comprises a latching member pivotallymounted relative to said hammers and simultaneously engageable with aportion of each of said hammers, said latching member being movable intoand out of the path of motion of said hammers.
 14. Apparatus as in claim13 further comprising means for moving said housing into at least threepositions relative to the paper, one of said positions being a printingposition.
 15. Apparatus as in claim 14 wherein said moving meanscomprises a first rotatable shaft connected to said housing. 16.Apparatus as in claim 15 wherein said moving means further comprises, asecond rotatable shaft connected to said housing, and means connectingsaid first and second shafts for transmitting movement of one of saidshafts to the other of said shafts, said second shaft having a firsteccentric member mounted thereon and connected to said housing to induceoscillatory movement of said housing between said three positions. 17.Apparatus as in claim 16 further comprising a second eccentric membermounted on said second shaft and connected to said first bridging meansto induce oscillatory movement in said bridging means simultaneouslywith said oscillatory movement of said housing.
 18. ApparatUs as inclaim 17 further comprising a plurality of restraining bails, each ofsaid bails being engageable with one of said hammers, and a plurality ofcam members connected to said second shaft, each of said cam membersbeing engageable with corresponding ones of said restraining bails formoving said bails selectively into and out of engagement with saidhammers.
 19. Apparatus as in claim 18 further comprising a cam memberperiodically engageable with said second bridging means to actuate saidlocking members.
 20. Apparatus as in claim 19 wherein each of saidrestraining bails is pivotally mounted on said first shaft. 21.Apparatus as in claim 20 wherein said housing is adapted for lateralmovement along said first shaft.
 22. Apparatus as in claim 21 furthercomprising carriage means having first bearings connected to said firstshaft and second bearings concentric with said first bearings for thepivotal bearing of said housing.
 23. Apparatus as in claim 22 furthercomprising an electronic storage register to emit electric impulses foractuating said electromagnetic means, a code member movablesynchronously with said first bridging means and having a plurality ofmachine readable code configurations, each of said configurationscorresponding to one type position of said type carrying members, andmeans for scanning said code configurations, said scanning means beingadapted according to a scanned code to emit an electric signal forsensing said storage register with respect to the presence of acorresponding character registration.